Description: When the conclusion does not follow from the premises. In more informal reasoning, it can be when what is presented as evidence or reason is irrelevant or adds very little support to the conclusion.

Logical Form:

Claim A is made.

Evidence is presented for claim A.

Therefore, claim C is true.

Example #1:

People generally like to walk on the beach. Beaches have sand. Therefore, having sand floors in homes would be a great idea!

Explanation: As cool as the idea of sand floors might sound, the conclusion does not follow from the premises. The fact that people generally like to walk on sand does not mean that they want sand in their homes, just like because people generally like to swim, they shouldn’t flood their houses.

Example #2:

Buddy Burger has the greatest food in town. Buddy Burger was voted #1 by the local paper. Therefore, Phil, the owner of Buddy Burger, should run for president of the United States.

Explanation: I bet Phil makes one heck of a burger, but it does not follow that he should be president.

Exception: There really are no exceptions to this rule. Any good argument must have a conclusion that follows from the premises.

Tip: One of the best ways to expose non sequiturs is by constructing a valid analogy that exposes the absurdity in the argument.

Variations: There are many forms of non sequiturs including argument by scenario, where an irrelevant scenario is given in an attempt to support the conclusion. Other forms use different rhetorical devices that are irrelevant to the conclusion.

False or questionable premises could be seen as errors in facts, but they can also lead to the conclusion not following, so just keep that in mind, as well.

Is it a non-sequitur when someone responds to an argument with a completely irrelevant rebuttal that doesn't address the argument at all? For example, two people are discussing the protests and riots in Ferguson after the shooting of Michael Brown. One person, Jon, takes the position that there were both peaceful protests and riots. The other person, Mike, believes there was only riots. Mike makes the argument that he only remembers seeing media coverage of the riots, therefore there were only arguments. Jon responds:

Jon: Your perception of reality is shaped by the media you consume. If you mostly consume right wing media, you'll mostly hear the protests described as riots and misrepresentations of why the black community is upset.

Mike: There is no excuse for rioting.

How does Jon respond to this? Is this a non-sequitur? Jon hasn't offered any excuses for rioting.

Is this a non sequitur? Joe- 99% of climate sciences worldwide accept the fact of anthropogenic climate change.

Jill- Well here is a paper written by a scientist that doubts anthropogenic climate change. Therefor anthropogenic climate change is just natural cycles and not man made.

Joe- I know there are a small handful of published papers denying anthropomorphized climate change. But there are millions supporting it. If I gave you a lottery number that had a 1% chance of winning, vs a number that had a 99% chance of winning, you'd pick the one that had the 99% chance of winning because its way more probable if not basically certain. The only reason you'd cling to the 1% is if you had a bias or agenda to uphold.

Jill- So years ago in class I took an exam and the entire class failed but I was the only who passed. By your logic this couldn't be because the 99% has to be right and the 1% can't possibly be.This debate is getting old. Your stuck with your belief so good for you. By the way smart guy learn how the science community works before you go attempting to correct someone about a subject matter you know very little about. When scientist are funded they will not publish papers going against who is funding them. That is a fact.﻿

I see no non-sequitur. Joe is deferring to an overwhelming scientific consensus on a scientific issue. Perfectly reasonable. Jill is reasoning inconsistently because she is ignoring her own argument—the many studies on climate change funded by organizations who have a financial interest is ignoring climate change.

@Bo Bennett, PhD: What fallacy would the, "So years ago in class I took an exam and the entire class failed but I was the only who passed. By your logic this couldn't be because the 99% has to be right and the 1% can't possibly be." be?

Would enthymemes(arguments with a missing premise or conclusion) be an example of a non-sequtur? The reason I ask this is because I think that sometimes if one omits a point, then it may not be apparent how the conclusion follows from a premise.

Is this a non sequester fallacy: 1- Only intelligent human minds intentionally create complex things with purpose and intent. 2- The universe is a complex thing. 3- Therefor God is a human like being who created the universe with purpose and intent.

Become a Logical Fallacy Master. Choose Your Poison.

Logically Fallacious is one of the most comprehensive collections of logical fallacies with all original examples and easy to understand descriptions; perfect for educators, debaters, or anyone who wants to improve his or her reasoning skills.

Get the book, Logically Fallacious by Bo Bennett, PhD by selecting one of the following options: